Hi Andreas,
The UV(W) information created is a constant flow along the spline.
If the shown model is close to your problem, try Cubic Projection.
Making it “editable” is the next suggestion, as the UV in the Generated object allows for no access.
The “internal” UV production is based on the points given to the spline. This is the only possible manipulation to my knowledge.
To show case this, please have a look at the file below:
Scene File
https://www.amazon.com/clouddrive/share/2cpI4IW4JXNDsbTZytr79M4CZ2GKnDcUDVD7of6G5dY?ref_=cd_ph_share_link_copy
Illustration:
https://www.amazon.com/clouddrive/share/eGRiLNFadaJMTYwBaHJQI8SWlhmzLPANbB7arLv4jNR?ref_=cd_ph_share_link_copy
From point to point the UV space is the same in terms of Image space. So places more points somewhere will change everything.
Using Subdivided in the interpolation method, and use the Object Manager> Object>Current State To Object to create a new Spline is maybe one of the fastest ways.
Screen-shot, with low max distance.
https://www.amazon.com/clouddrive/share/e5DI28jvKS3sOb6IuLsBgK9ndlxFaUfTAuKw2OolNos?ref_=cd_ph_share_link_copy
Click on the HUD element to see (or not) the Illumination or Color. I added as well an Atom Object, when active it shows clearly the mesh.
If you like, you can submit a suggestion, perhaps something like the Correction Deformer, but for UV data.
https://www.maxon.net/en-us/support/suggestions/
All the best
